Graptolite evidence for the ages of the Sofala Volcanics and Willow Glen Formation, northern Capertee High, N.S.W.
New finds of graptolites in the Cudgegong district, N.S.W., indicate a Bo3 (mid-Bolindian: Late Ordovician) age for the upper part of the Sofala Volcanics and an early Prídolí (Late Silurian) age for the upper part of the Willow Glen Formation. The Silurian graptolite is described as Monograptus parultimus minutus subsp. nov. Integration of the new biostratigraphic data with SHRIMP ages for volcanic units in the Cudgegong sequence supports an age of 410 Ma for the Silurian-Devonian boundary.